Strack, Philipp

Tuesday December 20, 2011
Time: 13:45
Place: HIT H 42
Host: Tilman Esslinger

Tunable quantum glasses and phase transitions of atoms and photons: first testable predictions for glassy physics with many-body cavity QED

Philipp Strack
Harvard University, Cambridge, USA

Recent studies of strongly interacting atoms and photons in optical cavities have rekindled interest in the Dicke model of atomic qubits coupled to discrete photon cavity modes. In this talk, we argue that realizations of the Dicke model with variable atom-photon couplings can give rise to a ground state phase diagram exhibiting quantum phase transitions between paramagnetic, ferromagnetic, and a spin glass phase. These quantum optics realizations of quantum glasses are distinctive to condensed matter systems and provide new opportunities for glassy physics with many-body cavity QED. The photon-mediated random couplings between the atomic qubits (Ising spins) are truly long-ranged and the theory for these systems remains analytically tractable. We compute atomic and photon spectral response functions across this phase diagram, and outline how our predictions can be observed in experiments.